Plenty of gray hairs and 1960s-'70s musical nostalgia, on stage and off, at the South Shore Music Circus Saturday night, but also a couple hours of warm feelings and topnotch musicianship, as "The Turtles, with Flo & Eddie" and their latest version of the annual Happy Together Tour hit Cohasset before a crowd of about 2000 giddy fans.

No less than four acts preceded the headliners, all backed by a crack four-piece band of (slightly) younger musical pros, including bandleader Godfrey Townsend on guitar, drummer/vocalist Steve Murphy, bassist John Montana, and keyboardist Manny Focarazo. The lineup; Gary Lewis of the Playboys, Mitch Ryder of the Detroit Wheels, Mark Farner of Grand Funk Railroad, and Chuck Negron of Three Dog Night each did approximately 20-minute sets, which translated to about four songs on average. The Turtles' headlining set was a bit longer, and featured one final jam-out, where each previous performer returned for a brief reprise of their best-known hit.

The Turtles, whose meteoric shot across the pop charts lasted from 1965-70, have been doing these Happy Together tours, featuring a changing cast of characters, since 1984, or shortly after Turtles frontmen Howard Kaylan and Mark Volman regained legal rights to the band name. After the original Turtles dissolved in 1970 amid record label hassles--including demanding that Volman and Kaylan fire their bandmates and record and tour with hired hands--the two principals joined Frank Zappa's band, under the pseudonyms Flo & Eddie. Eventually they began releasing music under that name, while still maintaining the connection with Zappa's group.

As Kaylan noted Saturday, the first version of the Happy Together tour played just 16 dates, while this year's edition is performing at 56 different venues. It's a fast-paced evening, heavy on the hits, with gracious and charming music veterans seemingly just as eager to reunite with their fans as the audience is to see and hear them all these years later.

Personally, I'd like to hear more of the Turtles, as their unique blend of poppy folk-rock and good-natured weirdness is guaranteed to provoke smiles on the most cynical music fan. The Turtles came charging down the ramp to the stage, with Volman in a bright, sparkly green jacket, his bushy hair bouncing as he cavorted around the stage, while Kaylan made a more dignified entry in his black pork-pie hat, and a white sportcoat decorated with little black palm trees. That exuberant entrance led easily into the buoyant "She'd Rather Be With Me," a nugget from their first year as rock stars, '65.

The sweet crooning melody of "You Baby," also from '65, was another keepsake moment, and it was obvious Kaylan still has terrific vocal ability. Volman seemed to confine himself to harmonies, and some points all four of the backing musicians were also adding to the delectable vocal harmonies. How many fans recalled that the Turtles' first hit was a remake of a Bob Dylan tune? "It Ain't Me Babe" was every bit the neatly re-done gem it was way back then, folk-rock imbued with Beach Boys-style vocals, which was a natural effect given that the Turtles were basically California teenagers at the time. 1968's "Elenore" was a more conventional pop ballad, although still irresistibly bouncy, and then of course the mass singalong/love-in that is the song "Happy Together" was the climactic moment, leading to that big finale of mini-encores by everyone else.

Earlier Chuck Negron had proven to be a fine vocalist on his own--Three Dog Night featured three lead singers, including Cory Dells and Danny Hutton. Three Dog Night dominated the charts, to the tune of 12 gold albums, from 1968-76, when they broke up, before reuniting in '81. (Negron left the band in 1985, struggling with substance abuse, while the others have continued performing, off and on, to the present day, when Hutton and Dells still front a version of Three Dog Night.)

Negron, looking spiffy in his black sportcoat over a salmon-colored shirt, with aviator shades and a head of luxuriant brown hair, opened with a vibrant take on "Mama Told Me Not to Come." Three Dog Night used a wide variety of songwriters, and that song was from Randy Newman, while the rapidly rock-paced "Eli's Coming" from 1969 was a Laura Nyro tune. At the end of that showstopper, Negron admitted that he'd never realized he'd still be singing that song "in my mid-fifties.." As the crowd gave out a collective chuckle, Negron admitted he is the oldest trouper on this tour, at 72. "I figure I'll have one or two more kids and then take it easy.." he said.

Comedy aside, Negron did a fabulous job on Harry Nilsson's "One (Is the Loneliest Number)," and then finished his set with 1971's Record of the Year, which was one of his lead vocals back in the day, on "Joy to the World," the Hoyt Axton tune perhaps best known for its opening line "Jeremiah was a bullfrog.."

Just before intermission, Grand Funk Railroad's former lead singer and guitarist Mark Farner electrified the crowd with his own dynamic set. (Original bassist Mel Schacher and drummer Don Brewer still perform with the Grand Funk RR name.) Farner, 65, appeared to be in the best shape of all the acts, in his tight tee-short and jeans, with his waist-length hair flowing as he roamed the circular stage playing his wireless guitar.

Farner hit the stage running at high speed with Grand Funk's rocked-up take on the old Little Eva hit, "The Loco-motion," and then led a pulverizing romp through "We're An American Band." The only quibble we'd have is that neither Farner's nor Townsend's guitar lines were very high in the mix, and Grand Funk was, after all, essentially a guitar band. Band drummer Murphy sang the lead on "Some Kind of Wonderful," Grand Funk's 1975 hit, and earned a loud ovation. Farner's crowning moment was a long and soulful take on "I'm Your Captain," where his passionate vocal and special guitar effects elevated that 1970 chestnut to new heights.

Mitch Ryder looked the most like today's rockers, in his black jeans, black tee, and black cap, but his raw-but-righteous vocals are still galvanizing at 69. With material like "C.C. Ryder" and his iconic garage-rocker "Devil With a Blue Dress," the Detroit legend was still a gritty whirlwind.

Gary Lewis, the son of comic Jerry Lewis, had a string of hits in the mid-1960s, none bigger than 1965's "This Diamond Ring"--which was penned by rock Zelig/now Berklee professor Al Kooper. Lewis sounded in vintage form on "This Diamond Ring" in his multi-colored/not-quite psychedelic sportshirt, and especially appreciative of the audience reaction. Lewis' music career never quite recovered after he was drafted and spent 1967-68 in the Army, serving in South Korea among other places. But just two years ago, Lewis, 69, released a new album, "The Promise."